<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Service
 * @subpackage Amazon
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Amazon.php 18951 2009-11-12 16:26:19Z alexander $
 */

/**
 * @see Zend_Rest_Client
 */
require_once 'Zend/Rest/Client.php';

/**
 * @category   Zend
 * @package    Zend_Service
 * @subpackage Amazon
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Service_Amazon
{
	/**
	 * Amazon Web Services Access Key ID
	 *
	 * @var string
	 */
	public $appId;

	/**
	 * @var string
	 */
	protected $_secretKey = null;

	/**
	 * @var string
	 */
	protected $_baseUri = null;

	/**
	 * List of Amazon Web Service base URLs, indexed by country code
	 *
	 * @var array
	 */
	protected $_baseUriList = array('US' => 'http://webservices.amazon.com',
                                    'UK' => 'http://webservices.amazon.co.uk',
                                    'DE' => 'http://webservices.amazon.de',
                                    'JP' => 'http://webservices.amazon.co.jp',
                                    'FR' => 'http://webservices.amazon.fr',
                                    'CA' => 'http://webservices.amazon.ca');

	/**
	 * Reference to REST client object
	 *
	 * @var Zend_Rest_Client
	 */
	protected $_rest = null;


	/**
	 * Constructs a new Amazon Web Services Client
	 *
	 * @param  string $appId       Developer's Amazon appid
	 * @param  string $countryCode Country code for Amazon service; may be US, UK, DE, JP, FR, CA
	 * @throws Zend_Service_Exception
	 * @return Zend_Service_Amazon
	 */
	public function __construct($appId, $countryCode = 'US', $secretKey = null)
	{
		$this->appId = (string) $appId;
		$this->_secretKey = $secretKey;

		$countryCode = (string) $countryCode;
		if (!isset($this->_baseUriList[$countryCode])) {
			/**
			 * @see Zend_Service_Exception
			 */
			require_once 'Zend/Service/Exception.php';
			throw new Zend_Service_Exception("Unknown country code: $countryCode");
		}

		$this->_baseUri = $this->_baseUriList[$countryCode];
	}


	/**
	 * Search for Items
	 *
	 * @param  array $options Options to use for the Search Query
	 * @throws Zend_Service_Exception
	 * @return Zend_Service_Amazon_ResultSet
	 * @see http://www.amazon.com/gp/aws/sdk/main.html/102-9041115-9057709?s=AWSEcommerceService&v=2005-10-05&p=ApiReference/ItemSearchOperation
	 */
	public function itemSearch(array $options)
	{
		$client = $this->getRestClient();
		$client->setUri($this->_baseUri);

		$defaultOptions = array('ResponseGroup' => 'Small');
		$options = $this->_prepareOptions('ItemSearch', $options, $defaultOptions);
		$client->getHttpClient()->resetParameters();
		$response = $client->restGet('/onca/xml', $options);

		if ($response->isError()) {
			/**
			 * @see Zend_Service_Exception
			 */
			require_once 'Zend/Service/Exception.php';
			throw new Zend_Service_Exception('An error occurred sending request. Status code: '
			. $response->getStatus());
		}

		$dom = new DOMDocument();
		$dom->loadXML($response->getBody());
		self::_checkErrors($dom);

		/**
		 * @see Zend_Service_Amazon_ResultSet
		 */
		require_once 'Zend/Service/Amazon/ResultSet.php';
		return new Zend_Service_Amazon_ResultSet($dom);
	}


	/**
	 * Look up item(s) by ASIN
	 *
	 * @param  string $asin    Amazon ASIN ID
	 * @param  array  $options Query Options
	 * @see http://www.amazon.com/gp/aws/sdk/main.html/102-9041115-9057709?s=AWSEcommerceService&v=2005-10-05&p=ApiReference/ItemLookupOperation
	 * @throws Zend_Service_Exception
	 * @return Zend_Service_Amazon_Item|Zend_Service_Amazon_ResultSet
	 */
	public function itemLookup($asin, array $options = array())
	{
		$client = $this->getRestClient();
		$client->setUri($this->_baseUri);
		$client->getHttpClient()->resetParameters();

		$defaultOptions = array('ResponseGroup' => 'Small');
		$options['ItemId'] = (string) $asin;
		$options = $this->_prepareOptions('ItemLookup', $options, $defaultOptions);
		$response = $client->restGet('/onca/xml', $options);

		if ($response->isError()) {
			/**
			 * @see Zend_Service_Exception
			 */
			require_once 'Zend/Service/Exception.php';
			throw new Zend_Service_Exception(
                'An error occurred sending request. Status code: ' . $response->getStatus()
			);
		}

		$dom = new DOMDocument();
		$dom->loadXML($response->getBody());
		self::_checkErrors($dom);
		$xpath = new DOMXPath($dom);
		$xpath->registerNamespace('az', 'http://webservices.amazon.com/AWSECommerceService/2005-10-05');
		$items = $xpath->query('//az:Items/az:Item');

		if ($items->length == 1) {
			/**
			 * @see Zend_Service_Amazon_Item
			 */
			require_once 'Zend/Service/Amazon/Item.php';
			return new Zend_Service_Amazon_Item($items->item(0));
		}

		/**
		 * @see Zend_Service_Amazon_ResultSet
		 */
		require_once 'Zend/Service/Amazon/ResultSet.php';
		return new Zend_Service_Amazon_ResultSet($dom);
	}


	/**
	 * Returns a reference to the REST client
	 *
	 * @return Zend_Rest_Client
	 */
	public function getRestClient()
	{
		if($this->_rest === null) {
			$this->_rest = new Zend_Rest_Client();
		}
		return $this->_rest;
	}

	/**
	 * Set REST client
	 *
	 * @param Zend_Rest_Client
	 * @return Zend_Service_Amazon
	 */
	public function setRestClient(Zend_Rest_Client $client)
	{
		$this->_rest = $client;
		return $this;
	}


	/**
	 * Prepare options for request
	 *
	 * @param  string $query          Action to perform
	 * @param  array  $options        User supplied options
	 * @param  array  $defaultOptions Default options
	 * @return array
	 */
	protected function _prepareOptions($query, array $options, array $defaultOptions)
	{
		$options['AWSAccessKeyId'] = $this->appId;
		$options['Service']        = 'AWSECommerceService';
		$options['Operation']      = (string) $query;
		$options['Version']        = '2005-10-05';

		// de-canonicalize out sort key
		if (isset($options['ResponseGroup'])) {
			$responseGroup = explode(',', $options['ResponseGroup']);

			if (!in_array('Request', $responseGroup)) {
				$responseGroup[] = 'Request';
				$options['ResponseGroup'] = implode(',', $responseGroup);
			}
		}

		$options = array_merge($defaultOptions, $options);

		if($this->_secretKey !== null) {
			$options['Timestamp'] = gmdate("Y-m-d\TH:i:s\Z");;
			ksort($options);
			$options['Signature'] = self::computeSignature($this->_baseUri, $this->_secretKey, $options);
		}

		return $options;
	}

	/**
	 * Compute Signature for Authentication with Amazon Product Advertising Webservices
	 *
	 * @param  string $baseUri
	 * @param  string $secretKey
	 * @param  array $options
	 * @return string
	 */
	static public function computeSignature($baseUri, $secretKey, array $options)
	{
		require_once "Zend/Crypt/Hmac.php";

		$signature = self::buildRawSignature($baseUri, $options);
		return base64_encode(
		Zend_Crypt_Hmac::compute($secretKey, 'sha256', $signature, Zend_Crypt_Hmac::BINARY)
		);
	}

	/**
	 * Build the Raw Signature Text
	 *
	 * @param  string $baseUri
	 * @param  array $options
	 * @return string
	 */
	static public function buildRawSignature($baseUri, $options)
	{
		ksort($options);
		$params = array();
		foreach($options AS $k => $v) {
			$params[] = $k."=".rawurlencode($v);
		}

		return sprintf("GET\n%s\n/onca/xml\n%s",
		str_replace('http://', '', $baseUri),
		implode("&", $params)
		);
	}


	/**
	 * Check result for errors
	 *
	 * @param  DOMDocument $dom
	 * @throws Zend_Service_Exception
	 * @return void
	 */
	protected static function _checkErrors(DOMDocument $dom)
	{
		$xpath = new DOMXPath($dom);
		$xpath->registerNamespace('az', 'http://webservices.amazon.com/AWSECommerceService/2005-10-05');

		if ($xpath->query('//az:Error')->length >= 1) {
			$code = $xpath->query('//az:Error/az:Code/text()')->item(0)->data;
			$message = $xpath->query('//az:Error/az:Message/text()')->item(0)->data;

			switch($code) {
				case 'AWS.ECommerceService.NoExactMatches':
					break;
				default:
					/**
					 * @see Zend_Service_Exception
					 */
					require_once 'Zend/Service/Exception.php';
					throw new Zend_Service_Exception("$message ($code)");
			}
		}
	}
}
